I hadn't realized quite how many of the special-paper-free digital pens were out there now - last time I'd looked, the pens needed special paper and used a pen-tip camera for sensing (basically a special-purpose optical mouse).
Interestingly, the last three pens in the comparison table all do look very similar to Wacom's offering. I wonder whether the Wacom pen is using the same technology (or is maybe even made by the same manufacturer behind the scenes?)
In any case, I reckon the Wacom name will help them sell, possibly helping promote them to artists wanting to sketch on the move rather than (as the linked comparison mentions) for business purposes.
My guess is wacom managed to improve the quality enough to make it usable for artists. The other pens seem to be mainly useful for ocr, and are marketed as tools for taking notes.
The automatic vectorization of the drawings is also nice.
Here's a collection of them: http://digital-pen-review.toptenreviews.com/
Interestingly, the last three pens in the comparison table all do look very similar to Wacom's offering. I wonder whether the Wacom pen is using the same technology (or is maybe even made by the same manufacturer behind the scenes?)
In any case, I reckon the Wacom name will help them sell, possibly helping promote them to artists wanting to sketch on the move rather than (as the linked comparison mentions) for business purposes.